Because there are so few Proto-Sinaitic signs, little is known with certainty about the nature of the script. The script co-existed with Egyptian hieroglyphs, so it is likely that it represented true writing, but this is not certain. From the shape of the signs, Proto-Sinaitic may be an alphabet, and the ancestor of the Phoenician alphabet, from which nearly all modern alphabets descend.

There have been two major discoveries of inscriptions of the Proto-Sinaitic script. The first was in the winter of 1904–1905 in Sinai by Hilda and Flinders Petrie, dated to circa 1700–1400 BC. The second find was more recently in 1999 in Middle Egypt by John and Deborah Darnell. This is dated to the 18th century BC.[1]